Method for improving vision in a motor vehicle

ABSTRACT

A method, a device and a processing unit for improving visibility in a motor vehicle are described, a light source of the motor vehicle illuminating an illumination range. At least one monitoring sensor of the motor vehicle monitors the surroundings around the motor vehicle for the presence of objects. The light source is adjusted in such a way that the spatial and/or temporal irradiation of the objects which are present at least with light having wavelengths outside of the visible spectrum, e.g., near infrared light, is less than a specifiable limiting value.

FIELD OF THE INVENTION

The invention relates to a method and a processing unit for improvingvisibility in a motor vehicle, and its use in a night-view system in amotor vehicle.

DESCRIPTION OF RELATED ART

German unexamined patent application DE 40 32 927 describes a device forimproving visibility conditions in a motor vehicle. The image capturedusing an infrared-sensitive camera is visually superimposed onto theexterior landscape using a display device designed as a head-up display,and is displayed to the driver. Furthermore, at least one radiationsource with an infrared radiation component is provided for irradiatingthe viewing range seen by the driver in the direction of travel.

Night-view systems (NV systems) of this type, as described, e.g., in DE40 32 927, based on light having wavelengths in the near-infrared (NIR)wavelength range basically illuminate the scene in front of a motorvehicle using infrared headlamps (near-infrared headlamps, NIRheadlamps) with high-beam characteristics. Under certain conditions, NIRradiation—which is invisible to humans and most animals—can harm theeyes of humans and animals located in the effective range of an NIRheadlamp of this type. To prevent such harm, it is feasible to identifyminimum distances between NIR headlamps and the eye which must be metfor certain irradiation intensities, and which are ensured, e.g., usingdesign measures.

In addition to design measures, German unexamined patent application DE101 26 492 makes known an alternative method for ensuring harm to roadusers by NIR light. A method is provided, using which laser light havinga wavelength outside the visible spectrum is emitted only when the motorvehicle is in motion. It is furthermore known to not activate NIRheadlamps until a certain minimum velocity is reached, e.g., 30 km/h.The disadvantage of these methods is that the night-view functionalityof a night-view system is not available when the motor vehicle is at astandstill and/or when traveling at a slow rate of speed, even thoughsituations can occur in these cases in which the night-viewfunctionality would be useful. For example, a night-view functionalitywould be useful when traveling slowly on dirt roads or on narrow sidestreets. In addition, the service life of NIR headlamps is shortened ifthey are frequently switched on and off. A considerable load is placedon NIR headlamps in particular in a stop-and-go situation and/or indriving situations close to the minimum velocity. This limitedavailability can result in lower user acceptance for a night-view systemof this type.

The German unexamined patent applications DE 40 32 927 and DE 101 26 492mentioned above contain no mention of non-harmful, highly availablemethods for improving visibility in a motor vehicle.

SUMMARY OF THE INVENTION

In accordance with the invention there is provided a method forimproving visibility in a motor vehicle, at least one light source ofthe motor vehicle illuminating an illumination range, wherein at leastone sensor in the motor vehicle monitors at least part of theillumination range of the light source for the presence of at least oneobject, the sensor generating sensor signals as a function of the atleast one object which is present, the light source being adjusted as afunction of the sensor signals in such a way that the spatial and/ortemporal irradiation of the at least one object which is present atleast with light having wavelengths outside of the visible spectrum ofthe light source is less than a specifiable first limiting value.

An advantage of the invention is that it achieves reduction in the harm,in particular harm to the eyes, of objects, e.g., humans, such aspedestrians and/or cyclists and/or drivers and/or animals in theillumination range of the light source caused by the non-visibleradiation outside the visible spectrum.

Use of the method described below is particularly advantageous innight-view systems in motor vehicles with which a video sensor which issensitive in the visible spectral range at least and in the nearinfrared spectral range in particular detects the surroundings aroundthe motor vehicle and displays this information to the driver. Incontrast to the known methods, a minimum velocity is not required toactivate the headlamp nor, therefore, the night-view system. By way ofthe method described below, a night-view system may always be activatedin an advantageous manner when the sensors (monitoring sensors) detectan unoccupied “risky” region, i.e., no objects are located in the riskyregion, and/or they are further away than the minimum distance requiredto rule out harm. The method described below makes a contribution, in aparticularly advantageous manner, to a long service life of the lightsources used, in particular the headlamps which illuminate at least inthe near infrared wavelength range (NIR headlamps), and to highavailability of the light sources and, therefore, the night-view system.

Furthermore, the method is advantageous when motor vehicles are drivingin queues, since the presence of motor vehicles and/or their distancefrom the light sources, in particular from the NIR headlamps, isdetected by the monitoring sensors, e.g., a radar sensor, and they aredeactivated, for example, if the minimum distance from the lightsources, in particular NIR headlamps, is not met. As a result, harm topassengers of motor vehicles driving in front who look out of the backof their vehicles, and/or harm to the driver of the motor vehicledriving in front via the rearview mirror is advantageously reduced.

A further advantage of the method described below is that the methodprovides a high degree of freedom in terms of designing the light sourcewhich emits light having wavelengths outside the visible spectrum, inparticular an NIR headlamp. For example, the degree of freedom in termsof designing the light source with regard to emitted power and/or thespectral range used and/or illumination characteristics is high. Thismakes a contribution, in a particularly advantageous manner, to highperformance of the light source, in particular of the NIR headlamp, and,therefore, the night-view system, at low cost. It is particularlyadvantageous that the method enables optimal matching of headlamps, NIRheadlamps in particular, and video sensors of the night-view system towavelength-dependent reflectances in the natural surroundings.

The method described below is advantageous in terms of the manufactureand/or maintenance and/or demonstration of a light source which emitslight having wavelengths outside the visible spectrum, in particular anNIR headlamp and/or a night-view system equipped therewith, since harmto production personnel and/or workshop personnel is reduced. The methodis particularly advantageous with regard to demonstration modes of thenight-view system which are used to demonstrate the night-viewfunctionality on the sales floor to potential buyers of the motorvehicle, since, e.g., harm to individuals who happen to be standingaround, such as children whose eyes are at the level of the headlamps,is reduced.

It is particularly advantageous that at least one ultrasonic sensorand/or at least one radar sensor which preferably operates in the 24 GHzand/or 77 GHz wavelength range, and/or at least one LIDAR sensor and/orat least one video sensor (video camera, camera) generates sensorsignals, since the use of these sensors already provided in the motorvehicle for other functionalities results in minimal additional costs,since no additional hardware is required.

The deactivation and/or activation of the light source as a function ofthe sensor signals is advantageous, since this makes it possible toprovide a simple, economical possibility for adjusting the light source.

Adjusting the spatial and/or temporal intensity of the light from thelight source as a function of the sensor signals has the advantage thatharm to objects which are present is deliberately reduced by the factthat the spatial and/or temporal irradiation of the object which ispresent at least with light having wavelengths outside the visiblespectrum of the light source is less than a specifiable first limitingvalue. At the same time, the functionality of a night-view systemequipped in this manner does not limit the remaining detection ranges.This contributes to high availability. It is furthermore advantageous toperform an alternative or additional adjustment of the spectralcomposition of the light from the light source as a function of thesensor signals.

It is particularly advantageous to issue a warning to the at least oneobject which is present using an acoustic and/or optical warning signalif the spatial and/or temporal irradiation of the at least one objectwhich is present at least with the light having wavelengths outside thevisible spectrum of the light source is greater than a specifiablesecond limiting value, the second limiting value being less than orequal to the first limiting value, since, as a result, the availabilityof the light source, in particular the NIR headlamp, and/or thenight-view system is increased, since the object which is present iswarned before the light source is adjusted.

It is furthermore advantageous that sensor signals from at least twosensors are fused in such a way that the characteristic values of the atleast one object which is present are ascertained as a function ofweighted object features of this at least one object. By fusing thesensor signals, the method is made particularly rugged.

It is particularly advantageous that the at least one sensor generatessensor signals which represent the distance of the at least one objectwhich is present from the at least one sensor and/or the at least onelight source and/or the size and/or the shape of the at least oneobject.

The advantages of the method described above also apply for a deviceand/or a processing unit for improving visibility in a motor vehicle,and for the use of the device and/or the processing unit in a night-viewsystem in a motor vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in greater detail with reference to thefollowing drawings wherein:

FIG. 1 shows a block diagram of the preferred exemplary embodiment.

FIG. 2 shows the positions of the sensors in a motor vehicle of thepreferred exemplary embodiment.

FIG. 3 shows a flow chart of the method of the preferred exemplaryembodiment.

DETAILED DESCRIPTION OF THE INVENTION

A method, a device and a processing unit for improving visibility in amotor vehicle are described below, a light source of the motor vehicleilluminating an illumination range. At least one monitoring sensor ofthe motor vehicle monitors the surroundings around the motor vehicle forthe presence of objects. The light source is adjusted in such a way thatthe spatial and/or temporal irradiation of the detected objects whichare present at least with light having wavelengths outside of thevisible spectrum, e.g. near infrared light, is less than a specifiablelimiting value.

In the preferred exemplary embodiment, the space in front of two NIRheadlamps of a night-view system are monitored using sensors. As aresult, individuals and other objects located in front of the NIRheadlamps, and/or their distance from the NIR headlamps is detected and,if the minimum distance is not met, the NIR headlamps are deactivated.As an alternative to deactivating the two NIR headlamps, only oneheadlamp may be deactivated, so that the night-view functionality of thenight-view system remains available, at least to a limited extent.

As an alternative to deactivating at least one NIR headlamp, in avariation of the preferred exemplary embodiment, the output of the twoNIR headlamps or at least one NIR headlamp is reduced, so that, when thedistance is detected, no further harm is caused to the object. As analternative to or in addition to the reduction in output, in a furthervariation, certain wavelength ranges are deactivated, e.g., by switchingon certain optical blocking filters. Further, as an alternative or inaddition, the radiation characteristics are changed, e.g., viamechanical shielding and/or optical elements. In a further variation ofthe preferred exemplary embodiment, the light source is adjusted as afunction of the critical exposure time. The critical exposure time isthe time at which, from this point forward, harm to the human eye islikely. This makes it possible to adjust the light sources as a functionof the exposure time shortly before the critical exposure time isreached, rather than having to make the adjustment immediately.

Sensors are used in the preferred exemplary embodiment which are alreadypresent in the motor vehicle, or whose use in motor vehicles is alreadyknown. They include, for example, park pilot sensors (PP sensors) basedon the use of ultrasound (ultrasonic sensors), long-range radar sensorshaving ranges of 77 GHz and more, as used in ACC (Adaptive CruiseControl), short-range radar sensors having a range of 24 GHz and less,or LIDAR sensors. As an alternative or in addition, a video sensor isused, in particular the video sensor for the night-view system which isalready installed. In one variation of the preferred exemplaryembodiment, sensor principles are used to monitor the illumination rangeof the light sources, in particular of the NIR headlamps, which areknown from safety technology and are used, e.g., to ensure safety indangerous regions of machinery. These include, e.g., laser scannersand/or photoelectric barriers and/or light section sensors.

In the preferred exemplary embodiment, the sensors are combined usingsensor fusion in such a way that the entire relevant space in front ofthe vehicle is monitored. The park pilot sensors monitor the closerange, up to approximately 3 meters in front of the motor vehicle, whilethe radar sensor monitors the long range of approximately 2 meters andfurther, and/or the video sensor monitors the region approximately 2meters and further in front of the windshield.

FIG. 1 shows a block diagram of the preferred exemplary embodiment,composed of sensors 10, 12, 14, a processing unit 16 and NIR headlamps18. Sensors 10, 12, 14 are located on a motor vehicle, as describedbelow with reference to FIG. 2. In the preferred exemplary embodiment,four ultrasonic sensors 10, one radar sensor 12 and one video sensor 14are used as sensors 10, 12, 14. Sensors 10, 12, 14 monitor theillumination range of NIR headlamps 18 in such a way that the monitoringranges which are not covered in their entirety individually by theillumination range of NIR headlamps 18 supplement each other in anoverlapping manner so that they monitor the entire illumination range ofNIR headlamps 18. In the preferred exemplary embodiment, video sensor 14and NIR headlamps 18 are components of a night-view system which issupplemented by a display device for depicting information from videosensor 14, the information being displayed to the driver. In thepreferred exemplary embodiment, a CMOS video camera is used. In avariation of the preferred exemplary embodiment, a CCD video camera isused as an alternative or in addition. The spectral range which isparticularly relevant for the night-view functionality is the spectralrange located above the visible spectrum (380 nm-780 nm) and within thesensitivity range of CCD or CMOS video cameras (approximately 350nm-1100 nm, based on the spectral sensitivity of silicon), i.e., between780 nm and 1100 nm. NIR IR-A is therefore particularly relevant for thenight-view functionality due to the sensitivity range of the videocamera. Headlamps are used as NIR headlamps 18 in the preferredexemplary embodiment which have halogen incandescent lamps having acolor temperature between 3200 and 3400° K., the spectral range of whichis limited by interference or absorption filters to the near infraredrange between approximately 780 nm and approximately 1200 nm. In onevariation of the preferred exemplary embodiment, laser headlamps areused as NIR headlamps 18. Laser headlamps have the advantage, incontrast to halogen incandescent lamps, that they are pulsed, preferablywith high frequency. This enables the laser headlamp to be synchronizedwith the illumination phase of the video camera. In a further variation,an array of light-emitting diodes (LEDs) is used as NIR headlamps 18. Inprinciple, any light source may be used, the spectral range of whichincludes at least the NIR IR-A range or parts thereof. The range whichis utilized is fixed, e.g., by using suitable optical filters. Inaddition, in a further variation of the preferred exemplary embodiment,the spectral range of NIR headlamp 18 is shifted in the NIR IR-A rangeusing non-linear methods of wavelength shifting, e.g., frequencydoubling. Depending on whether one or more objects are present, thesensors generate sensor signals which are transmitted via signal lines20 to processing unit 16. Processing unit 16 is composed of a pluralityof function modules 40, 42, 44, 46 shown in FIG. 3. Function modules 40,42, 44, 46 are implemented as programs and/or program steps of at leastone microprocessor in processing unit 16 and/or using programmablelogic, in particular as ASIC and/or FPGA. Processing unit 16 generatesadjustment signals for NIR headlamps 18 which are transmitted via signallines 20, the spatial and/or temporal irradiation of the at least oneobject which is present and which has been detected by sensors 10, 12,14 at least with the light having wavelengths outside the visiblespectrum of NIR headlamps 18 is less than a specifiable first limitingvalue. The visible spectrum is specified as the wavelength range ofelectromagnetic radiation which is perceived by the human eye. Accordingto DIN5030 Part 2, a distinction is made between the following spectralranges:

-   Near UV (UV-A): 315 nm-380 nm-   Visible light (VIS): 380 nm-780 nm-   Near infrared (NIR IR-A); 780 nm-1400 nm-   Near infrared (NIR IR-B): 1400 nm-3000 nm

Accordingly, the visible spectrum (VIS) is located in the wavelengthrange between 380 nm and 780 nm. Infrared radiation having wavelengthsgreater than 780 nm, in particular NIR IR-A in the wavelength rangebetween 780 nm to 1400 nm and NIR IR-B in the wavelength range 1400 nmto 3000 nm, and ultraviolet radiation (UV radiation) having wavelengthsless than 380 nm, in particular UV-A in the wavelength range between 315nm to 380 nm is therefore light having wavelengths outside the visiblespectrum. The data is transmitted electrically and/or optically and/orby radio via signal lines 20, signal lines 20 being a 1-wire line and/ora 2-wire line and/or a multiple-wire line. In particular, signal lines20 are designed, as an alternative or in addition, as a bus line, e.g.,the CAN bus.

FIG. 2 shows the arrangement of sensors 10, 12, 14 and their monitoringranges 26, 28, 30 in the area in front of motor vehicle 22 according tothe preferred exemplary embodiment. FIG. 2 is a top view of motorvehicle 22, which is traveling toward the left as shown in theillustration. Two NIR headlamps 18 are installed on the front of motorvehicle 22 in the region of the headlamps for low/high beams and/or inthe region of the additional headlamps and/or in the region of the foglamps in such a way that illumination ranges 32 in the direction oftravel substantially correspond to the illumination range of the highbeams. Furthermore, radar sensor 12 is installed in the region of theradiator grill and/or the front bumper of motor vehicle 22. According toa variation of the preferred exemplary embodiment, a LIDAR sensor isused as an alternative or in addition to radar sensor 12. Monitoringrange 30 of radar sensor 12 and/or the LIDAR sensor has an aperture ofapproximately 15° to 20°. Monitoring range 30 begins approximately 2meters in front of the sensor. In a further variation, scanning radar orLIDAR principles are used as an alternative or in addition. Monitoringrange 30 covered by these two sensor types is expanded by the scanningangle, which is not indicated in FIG. 2. In the preferred exemplaryembodiment, video sensor 14 is installed on the inside of windshield 24of motor vehicle 22. In addition to the monitoring functionality, videosensor 14 is also a component of the night-view system of the motorvehicle. Video sensor 14 is installed in the interior region of motorvehicle 22 in the region of the rearview mirror, the optical axis ofvideo sensor 14 for detecting the traffic space being oriented in such away that monitoring range 26 of video sensor 14 nearly coversillumination ranges 32 of NIR headlamps 18 in front of motor vehicle 22in the direction of travel. Monitoring range 26 of video sensor 14 hasan aperture in the direction of travel of approximately 30° and istherefore matched to the aperture of NIR headlamps 18, which is alsoapproximately 30°. The depth of focus range and, therefore, monitoringrange 26 of video sensor 14 begins approximately 2 meters in front ofvideo sensor 14. In addition, a cluster of four ultrasonic sensors 10 isshown in FIG. 2, which are distributed symmetrically across the frontbumper of motor vehicle 22. Ultrasonic sensors 10 are used as park pilotsensors to aid the driver in parking. As an alternative, in onevariation, a cluster of six ultrasonic sensors 10 is used. Monitoringrange 28 of ultrasonic sensors 10 covers an area of approximately 2 to 5meters, preferably 2 meters, around the front bumper of motor vehicle 22in the direction of travel. The cluster covers the entire area in frontof NIR headlamps 18. Based on monitoring ranges 28, 30, 32 of sensors10, 12, 14 shown, it is clear that the ranges directly in front of NIRheadlamps 18 in the preferred exemplary embodiment are detected by atleast two sensor types, i.e., the cluster of ultrasonic sensors 10 andvideo sensor 14. This contributes to high reliability of objectdetection.

FIG. 3 shows a flow chart of the method for improving visibility in amotor vehicle of the preferred exemplary embodiment, composed offunction modules 40, 42, 44, 46. FIG. 3 illustrates thesignal-processing structure for the monitoring carried out by the NIRheadlamps. The ultrasonic sensors, the radar sensor and the videosensors generate sensor signals in the form of object lists 48, 50, 52,54, 56, 58, each ultrasonic sensor generating an object list 48, 50, 52,54, the radar sensor generating object list 56, and the video sensorgenerating object list 58. Object lists 48, 50, 52, 54, 56, 58 containinformation about the object and/or the object position and/or at leastone parameter of the object which is present and has been detected bythe sensor. Object lists 48, 50, 52, 54, 56, 58 are transmitted tofunction module 40 for object fusion. There, they are fused in such away that the characteristic values of the least one object which ispresent are ascertained as a function of weighted object features ofthis at least one object. Object chart 60 created in function module 40contains the fused characteristic values of the objects, e.g., theposition of the objects and/or at least one characteristic value of theobjects, e.g., the height and/or width and/or shape of the objects. Theobjects in object chart 60 are forwarded to function module 42 forobject classification. Function module 42 transmits the data from objectchart 60 as data for object classification 62 to the video sensor which,based on its image information, classifies the objects based on theirsize and shape. In this manner, it is possible to distinguish irrelevantobjects, e.g., manhole covers, which are delivered by the radar sensor,from relevant objects, such as living beings. According to anothervariation, other surroundings sensors may be used for objectclassification as an alternative or in addition to the video sensor. Theonly precondition is that these surroundings sensors deliver otherrelevant data in addition to the distance away from the object, the databeing usable to classify objects. Function module 42 transmits chart 66of classified objects to function module 44 for classification of risk.Object tracking is carried out in function module 44 and/or functionmodule 46, so that a risk identifier is calculated for each object, therisk identifier taking into account the previous distance away from theNIR headlamp(s) and/or the exposure time elapsed so far. The functionmodule is based on a reference work 68 of harmful situations derivedfrom eye-safety guidelines. Reference work 68 is based on legalrequirements, in particular legal regulations regarding eye safety,and/or requirements voluntarily recognized by automotive manufacturersthemselves. Alternatively or in addition to this, this derivation takesplace as a function of the properties of the headlamps, in particularthe aperture and/or the spectral range used and/or the output and/or themotor vehicle type. The derivation of the first and/or second limitingvalue therefore takes place on an individual basis for each vehicleand/or each country. Typical values for the minimum distance—below whichthe light source is adjusted—are between approximately 40 cm andapproximately 15 m, depending on the design of the light source, inparticular of the NIR headlamp, and/or the exposure time. All classifiedobjects are evaluated in function module 44 with regard to their risk,based on reference work 68. As a result, a chart 66 of objects at riskis transmitted to function module 46 for use in controlling theheadlamp(s). To control the headlamp(s), function module 46 firstdetermines which of the NIR headlamps is affected based on the locationof the objects at risk. In the preferred exemplary embodiment, this. NIRheadlamp is then deactivated and/or switched off. In a variation of thepreferred exemplary embodiment, the output and/or at least one furtherparameter of the NIR headlamp, e.g., the spectral composition of thelight from the NIR headlamp, is controlled in such a way that, based onreference work 68 of harmful situations, one or both NIR headlamps is orare adjusted in such a way that the object is not harmed. To accomplishthis, the light source is adjusted in such a way that the spatial and/ortemporal irradiation of the at least one object which is present atleast with light having wavelengths outside of the visible spectrum ofthe light source is less than a specifiable first limiting value, thisfirst limiting value being derived from reference work 68. Bycontrolling the power, the spatial and/or temporal intensity of thelight from the NIR headlamp is adjusted. In the preferred exemplaryembodiment, two NIR headlamps are controlled, while only one or morethan two NIR headlamps are controlled in a further variation.

The method described and/or the device and/or the processing unit forimproving visibility in a motor vehicle becomes clear when NIR headlampsand/or light sources which emit light having wavelengths outside thevisible spectrum are automatically switched off when objects enter therisky range and/or remain in a range for longer than the describedlimiting values. This is detectable directly using an NIR-sensitivesensor and/or a sensor having a sensitivity at wavelengths outside thevisible spectrum and/or by monitoring the activation signals from lightsources, e.g., the trigger signals and/or the supply signals and/or theCAN messages. The distance-dependent deactivation and/or warning and/orreduction is detectable directly by monitoring the behavior of theheadlamps. Furthermore, the method described is detectable by monitoringthe communication between the sensors, the processing unit and thecontrol of the light sources.

The method and/or the device and/or the processing unit described arenot limited to the use in a night-view system with NIR headlamps.Rather, the method and/or the device and/or the processing unit areusable not only for night-view functions, but also for other automotivefunctionalities which operate using light having wavelengths outside thevisible spectrum, e.g., in communication between two motor vehicleswhich is based on infrared light. As an alternative or in addition,light sources are monitored which emit light having wavelengths in theultraviolet (UV) spectral range.

In a further variation, the described method and or the device and/orthe processing unit are used in the rear region of the motor vehicle,e.g., with an infrared-based backup camera.

With a further variation of the described method and/or the deviceand/or the processing unit, the monitoring for the close range of thelight sources is refined in such a way that living objects, such ashumans, are distinguished from devices, such as headlamp adjustmentdevices. The light sources are adjusted as a function of the vitality ofthe objects which are present. The determination of the vitality of theobjects which are present is ascertained either via the size of theobject and/or the shape of the object and/or the backscatter factorand/or the temporal tracking of the objects. For example, a headlampadjustment device for both headlamps is larger than a human due tomechanical integration and composition. Furthermore, a headlampadjustment device has a different shape than a human. Another variationprovides for differentiation based on the backscatter factor, e.g., byselecting a material for the headlamp adjustment device which has abackscatter factor which differs markedly from that for a human, therebyallowing differentiation by the ultrasonic sensor, for example. As analternative or in addition, in a further variation, a stationaryheadlamp adjustment device is distinguished from a moving human bytracking objects and classifying their speed.

In a further variation of the preferred exemplary embodiment, as analternative or in addition, an acoustic and/or optical warning signalwarns the at least one object which is present if the spatial and/ortemporal irradiation of the at least one object which is present atleast with the light having wavelengths outside the visible spectrum ofthe light source is greater than a specifiable second limiting value,the second limiting value being smaller than or equal to the firstlimiting value. In this variation, it is possible to warn humans inadvance. For example, an object which is detected at close range may bewarned acoustically, e.g., by a horn, or using optical signals, e.g., byflashing the headlamps and/or by a flashing warning light, with visiblelight. If, after a certain waiting period which is shorter than thecritical exposure time, the object is still in the risky range, thelight source affected—in particular the NIR headlamps of the night-viewsystem—are deactivated. The light source, in particular the NIRheadlamp, is reactivated when the object leaves the risky range and/ornot until the actual value falls back below the first limiting value.

1. A method for improving visibility in a motor vehicle, the motorvehicle having at least one light source illuminating an illuminationrange, comprising: monitoring at least part of the illumination range ofthe light source for the presence of at least one object using at leastone sensor in the motor vehicle, the sensor generating sensor signals asa function of the at least one object which is present, and adjustingthe light source as a function of the sensor signals in such a way thatthe spatial or temporal irradiation of the at least one object which ispresent at least with light having wavelengths outside of the visiblespectrum of the light source is less than a specifiable first limitingvalue.
 2. The method according to claim 1, wherein the light source is aheadlamp which emits illumination at least in the near-infraredwavelength range.
 3. The method according to claim 2, wherein the sensorsignals are generated by an ultrasonic sensor, a radar sensor, a LIDARsensor or a video sensor.
 4. The method according to claim 3, whereinthe radar sensor operates in a wavelength range of 24 GHz or 77 GHz. 5.The method according to claim 2, wherein the sensor signals aregenerated by an ultrasonic sensor, a radar sensor, a LIDAR sensor or avideo sensor.
 6. The method according to claim 1, wherein the lightsource is deactivated or activated as a function of the sensor signals.7. The method according to claim 2, wherein the light source isdeactivated or activated as a function of the sensor signals.
 8. Themethod according to claim 3, wherein the light source is deactivated oractivated as a function of the sensor signals.
 9. The method accordingto claim 1, wherein the spatial or temporal intensity of the light fromthe light source is adjusted as a function of the sensor signals. 10.The method according to claim 2, wherein the spatial or temporalintensity of the light from the light source is adjusted as a functionof the sensor signals.
 11. The method according to claim 3, wherein thespatial or temporal intensity of the light from the light source isadjusted as a function of the sensor signals.
 12. The method accordingto claim 1, wherein the spectral composition of the light from the lightsource is adjusted as a function of the sensor signals.
 13. The methodaccording to claim 2, wherein the spectral composition of the light fromthe light source is adjusted as a function of the sensor signals. 14.The method according to claim 3, wherein the spectral composition of thelight from the light source is adjusted as a function of the sensorsignals.
 15. The method according to claim 1, wherein an acoustic oroptical warning signal warns the at least one object which is present ifthe spatial or temporal irradiation of the at least one object which ispresent at least with the light having wavelengths outside the visiblespectrum of the light source is greater than a specifiable secondlimiting value, the second limiting value being less than or equal tothe first limiting value.
 16. The method according to claim 2, whereinan acoustic or optical warning signal warns the at least one objectwhich is present if the spatial or temporal irradiation of the at leastone object which is present at least with the light having wavelengthsoutside the visible spectrum of the light source is greater than aspecifiable second limiting value, the second limiting value being lessthan or equal to the first limiting value.
 17. The method according toclaim 3, wherein an acoustic or optical warning signal warns the atleast one object which is present if the spatial or temporal irradiationof the at least one object which is present at least with the lighthaving wavelengths outside the visible spectrum of the light source isgreater than a specifiable second limiting value, the second limitingvalue being less than or equal to the first limiting value.
 18. A devicefor improving visibility in a motor vehicle, for carrying out the methodaccording to claim 1, having at least one light source of the motorvehicle, the light source illuminating an illumination range,comprising: at least one sensor in the motor vehicle, the sensor beingconfigured in such a way that the sensor monitors at least part of theillumination range of the light source for the presence of at least oneobject, the sensor generating sensor signals as a function of the atleast one object which is present, and at least one processing unitwhich adjusts the light source as a function of the sensor signals insuch a way that the spatial or temporal irradiation of the at least oneobject which is present at least with light having wavelengths outsideof the visible spectrum of the light source is less than a specifiablefirst limiting value.
 19. A processing unit for improving visibility ina motor vehicle, for carrying out the method according to claim 1, theprocessing unit having at least a first interface for receiving sensorsignals of at least one sensor in the motor vehicle, comprising: meansfor processing the sensor signals, the sensor signals containinginformation about the presence of at least one object within at leastone part of an illumination range—of at least one light source—monitoredby the sensor, means for generating adjustment signals for the lightsource, the adjustment signals being produced as a function of thesensor signals in such a way that the spatial or temporal irradiation ofthe at least one object which is present at least with light havingwavelengths outside of the visible spectrum of the light source is lessthan a specifiable first limiting value, and at least one secondinterface for transferring the adjustment signals which were produced tothe light source.